Rear quarter window stuck down

[Marcosmate]

Hi all, newbie Ron here, rear quarter window dropped and would not go back up, I removed the interior trim panel , seat ,etc and can see that the problem is a snapped cable. What I need to know is how to fit a new cable, looks to me as if I have to remove the whole mechanism to get access to the winder assembly and it looks as if this is via the wheel arch outside of the car as I cannot see a way to remove the winder from inside the car! Any help would be much appreciated,thanks a lot.